This invention relates to di(hydroxyalkyl)aminoalkylsulfonamide and di(hydroxyalkyl)aminoalkylcarboxamide pigment derivatives that can be used to improve the performance of pigments used in coating systems.
The synthetic steps used in the manufacture of known organic pigments is generally straighfforward. Typically, however, the initially formed crude compounds are unsuitable for use as pigments and must undergo one or more additional finishing steps to modify the particle size, particle shape, or crystal structure to achieve suitable pigmentary quality, rheological properties, and dispersibility.
Such improvements can often be achieved by treating the organic pigments with various additives, including various sulfonic acid and carboxylic acid derivatives of organic pigments. E.g., U.S. Pat. Nos. 3,418,322, 3,446,641, 4,088,507, 4,310,359, and 5,368,641 and British Patents 1,544,839 and 2,009,205.
Among the organic pigment derivatives that can be used to improve pigment performance are dialkylaminoalkylsulfonamide and dialkylaminoalkylcarboxamide derivatives. For example, U.S. Pat. No. 5,368,641 discloses quinacridone pigment derivatives having the formula ##STR2## in which Q is a quinacridone radical; A can be, inter alia, sulfonamide or carboxamide groups connected through alkylene groups to the Y group; Y is -NR.sup.4 R.sup.5 (in which R.sup.4 and R.sup.5 are hydrogen or C.sub.1 -C.sub.22 alkyl or alkylene) or a five- to seven-membered heterocyclic group (which can optionally be substituted); and n is 1 to 4. This patent, however, does not disclose pigment derivatives in which R.sup.4 and R.sup.5 are substituted alkyl groups and does not disclose the use of the disclosed compounds for waterborne systems.
U.S. Pat. No. 4,310,359 discloses pigment derivatives having the formula ##STR3## in which Q is the residue of a pigment other than a phthalocyanine; X is -SO.sub.2 - or -CO-; R is hydrogen, alkyl, or alkenyl; R.sub.1 and R.sub.2 are independently hydrogen or optionally substituted alkyl or alkenyl or R.sub.1 and R.sub.2 taken together form a heterocyclic ring; m is 1 to 4; and n is 1 to 6. This patent, however, does not describe specific substituted alkyl groups and does not disclose the use of the disclosed compounds in waterborne pigment systems.
It has now been found that organic pigments treated with di(hydroxyalkyl)aminoalkyl-containing pigment derivatives according to the invention are not only suitable for use in waterborne coating systems but also exhibit improved coloristic and rheological properties compared to organic pigments treated with dialkylaminoalkyl-containing pigment derivatives.